This invention relates to sintering silicon carbide.
Silicon carbide is a strong, oxidation-resistant ceramic material which retains its strength even at high temperatures. It is thus useful in many high temperature structural applications, e.g., turbines.
Silicon carbide typically exists as a powder. In order to prepare high strength products, it is necessary to densify the powder. This is usually done by compacting the powder under pressure and subsequently heating it in the absence of pressure (pressureless sintering), or by simultaneously heating and compacting the powder under pressure (hot pressing). When pressureless sintering is used, it is necessary to employ a sintering aid because without such an aid silicon carbide will not densify, as is true of most covalently bonded materials.